Acute inflammation is a major cause of morbidity and mortality in medicine today. Many common disorders of the urogenital tract involve some aspect of acute or chronic inflammation. Examples of specific disorders include: pyelonephritis, cystitis, epididymitis, orchitis, and prostatitis. In addition to acute infectious etiologies, it is becoming increasingly clear that ischemia/reperfusion injury triggers a striking acute inflammatory response that contributes to tissue damage and organ failure. Examples is ischemic injury in the urogenital tract include renal transplantation, trauma, parenchymal sparing surgery for cancer, and torsion of the spermatic cord. I hypothesize that one of the earliest events to occur during an acute inflammatory response is the expression of endothelial cell adhesion molecules. This proposition is supported by a large body of in vitro and in vivo data examining endothelial cell activation. E- selectin is unique among adhesion molecules because it is found only on activated endothelial cells. B-selectin has been shown to be an important regulator of early leukocyte adhesion. Understanding the role of E- selectin in vivo has been difficult primarily because a lack of bioactive molecular probes and antibodies, especially for use animal models. I propose to use the rat kidney and heart as model tissues to study in vivo expression of E-selectin during acute inflammation induced by injection of lipopolysaccharide or ischemia/reperfusion injury. Initial studies will focus on a detailed characterization of E-selectin mRNA expression, using recently cloned rat E-selectin cDNA fragments. Novel studies, using RNase protection assays, will be performed to investigate preliminary evidence for the existence of E-selectin mRNA splice variants. Another objective of these experiments is to generate antibodies to characterize protein expression of E-selectin during acute inflammation. The time course and phenotype of infiltrating leukocytes will be studied, using immunocytochemistry, and these data compared to the time course of E- selectin gene expression. The goal of this project is to gain insight into cellular and molecular mechanisms regulating expression of E- selectin. Long term objectives include applying information on these regulatory mechanisms to the study of acute and chronic inflammatory disorders of the urogenital tract. To the best of my knowledge no other laboratory possesses the molecular tools to investigate such novel aspects of E-selectin, in vivo. Data obtained from these proposed studies would impact on a number of conditions affecting urogenital organs and set the stage for later investigations focus on chronic inflammatory disorders (i.e. interstitial cystitis, prostatitis, inflammatory aspects of prostatic hypertrophy).